Solar cells have attracts attention as natural energy sources. In the conventional solar cells, a silicon based solar cell has been a mainstream. The silicon based solar cell has achieved a power generation efficiency of 10% or more. On the other hand, in the case of a dye-sensitized solar cell, constant power generation efficiency is obtained by using titanium oxide particles as an electrode material.
Incidentally, the solar cell is literally a cell that uses sunlight and the production of electricity changes according to the amount of sunlight. Thus, when the amount of sunlight rapidly changes, the production of electricity is rapidly reduced. The silicon based solar cell is sensitive to changes in the amount of sunlight. If an abrupt change in the weather occurs, a phenomenon in which the production of electricity rapidly becomes zero is caused. In order to solve the problem, there is a need for a secondary battery which can store electricity efficiently.